Air-cooled hoist



1965 w. M. MARKS ETAL 3,214,140

AIR-COOLED HOIST 2 Sheets-Sheet 1 Filed March 20, 1963 William M Mar/rs and Norman 0. Dyer INVENTOR BY oh W, ,w 9 W Oct. 26, 1965 Filed March 20, 1963 W. M- MARKS ETAL AIR-COOLED HOIST 2 Sheets-Sheet 2 Norman D. Dyer INVENTOR.

BY E C'Y/ #7 United States Patent 3,214,140 AIR-COOLED HOIST William M. Marks and Norman D. Dyer, Beaumont, Tex., assignors to Dresser Industries, Inc., a corporation of Delaware Filed Mar. 20, 1963, Ser. No. 266,560 4 Claims. (Cl. 254-186) This invention relates to improvements in hoisting apparatus having air-cooled brakes. It is particularly useful in hoists of drawworks employed in rotary drilling rigs, but it is not limited to such use.

In the rotary drilling of wells, such as oil and gas wells, the drawworks hoists must control very heavy loads which may reach into the range from 200,000 to 500,000 pounds. When handling heavy loads, the braking mechanism of the hoist generates large quantities of heat which must be dissipated rapidly. Various air-cooling systems for braking mechanisms of hoists have been suggested as, for example, U.S. Patents Nos. 1,994,689 and 1,761,827. Such air-cooling systems are excellent when generation of heat is not too rapid and excessive; but under the heavy load conditions of modern, deep-well drilling, it is the common practice to use Water-cooled hoists.

Oil and gas wells usually are drilled at remote locations and often under desert and/ or severe weather conditions. Hauling water to rigs in desert locations is time consuming and expensive. When the weather is cold, anti-freeze must be added to the water, and this can become quite expensive when several thousand gallons of water are consumed. Even the best of water-cooled systems often develop leaks after long periods of use, and leakage onto the drilling floor adds to the adverse conditions under which the driller and floor men normally work.

Suggestions have been made for decreasing the disadvantages of Water-cooled hoists by combining air cooling with supplementary water cooling as, for example, U.S. Patents Nos. 2,412,706 and 2,982,378. Use of air cooling when the loads are light and little heat is generated, supplemented by water cooling when heat is developed at hight rate, decreases the disadvantages of water cooling by decreasing the time it must be used; but the distadvantages, although existing for a reduced proportion of the total time, are still present. Although it has long been known that air cooling, if sufliciently efficient, would eliminate the disadvantages of water cooling, and these disadvantages have been known to both manufacturers and users of drilling equipment, no air-cooled hoist having a cooling system sufficiently eflicient for such heavy service has been available.

It is an object of this invention to provide an improved air-cooled hoist which has a cooling system sufficiently efiicient to cool the brakes under the heavy load and high friction conditions encountered in drilling deep wells.

Another object is to provide a hoist of the above type which is self contained and requires no separate air supply.

Another object is to provide a hoist having an improved air-cooling system in which parts cooperate to provide improved utilization of air flow and to increase heat transfer to cooling air.

Another object is to provide a hoist of the above type in which air flow prevents trash, drops of oil or debris from entering the brakes.

Another object is to provide a hoist in which the brakes are visible, and the condition of brake shoes and linings can be observed by the operator at all times.

Still another object is to provide a hoist of the above type which is economical in construction and is practical for oil field use.

Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, the attached claims and the annexed drawings.

The present invention contemplates a hoist having a rotatable spool including a pair of outturned flanges attached to or integral with the spool. One of this pair of flanges is disposed near to an end of the spool and the other flange near to the opposite end thereof, thus defining a line-winding space between the flanges. A pair of cylindrical brake drums are singly disposed upon a corresponding one of each of these flanges in substantially air-tight relationship therewith. The brake drums have external braking surfaces of substantially the same diameter as the diameter of the flanges, and the braking surfaces extend from the flanges in a direction parallel to the central axis of the hoist outward from the line-winding space between the flanges. Brake bands are disposed around each of the brake drums, and these brake bands have inner braking surfaces corresponding with external braking surfaces on the drums. The brakes are thus of the externally contracting band type.

A pair of stationary cylindrical guard members are disposed to enclose the brakes. The guard members have end walls perpendicular to the spool, disposed near to the ends of the brake drums opposite the line-winding space. This end of each guard member is closed, and the guard extends from this closed end toward the line-winding space for a distance suflicient to overlap the brake shoes and flanges but does not extend into the line-winding space. The guard encloses a space radially outward from the brake bands which is considerably larger in cross section than the annular spaces between the ends of the brake shoes and the end walls of the guard member perpendicular to the spool.

This arrangement of flange and guard member thus provides spaces between each of the flanges and corresponding guard member. A centrifugal fan is disposed in each of these spaces, and the fans are disposed to be driven by rotation of the spool. Each of the fans comprises a series of flat, straight, radial vanes arranged in an annular area concentric with the spool carried upon suitable members attached to the spool and rotating therewith. Each of the brake drums has radial fins upon its inner surface arranged so that a fin is adjacent to each of the radial vanes.

It will be seen that with this arrangement, as the spool rotates, the vanes of the fan and fins on the inner side of the brake drums rotate with it, and that an effluent from the fan is conducted across substantially the entire inner surface of the brake drum and across the surface of fins thereon in a direction outward from the linewinding space until the efiiuent impinges upon the closed end wall of the cylindrical guard member. The direction of air flow is then changed so that air flows between an end of the brake shoe adjacent to the guard member radially outward and is deflected by the guard member to a path leading directly to the line-winding space. Thus, all effluent passes in direct heat exchange relationship with the inner side of the brake drum and fins attached thereto; and with some pressure drop and expansion occurring in the space between the end of the brake drum and guard member, there is some cooling of the heated eflluent by expansion, and the expanded effluent is then passed in heat exchange relationship with the brake band. When the brake band is released and out of contact with the braking surface of the brake drums, there will be flow of cooling air between the brake band and brake drum across the braking surfaces of each.

It will also be seen that with straight, radial, flat vanes in the centrifugal band the flow of air is always in the same direction without regard to the direction which the spool is rotated. Maximum cooling effect of air passed over the brake mechanism is thus obtained. Large volumes of air may be moved by the fan and the increased surface for heat exchange provided by fins on the inner surface of the brake drum adds to the efliciency of the cooling system. The guard member is open on the end adjoining the linewinding space and thus provides a large space between the periphery of the flanges and the guard member through which the condition of the brakes is visible to the operator at all times while continuous flow of air across the brakes into the line-winding space prevents debris, drops of oil, etc. from entering the brake system.

In the attached drawings, wherein like reference numerals indicate like parts throughout:

FIG. 1 illustrates schematically a fragmentary sectional view of one embodiment of this invention;

FIG. 2 illustrates a preferred type of fan vane made integral with a brake drum and serving both as heattransfer fin and fan vane; and

FIG. 3 is a fragmentary end elevation of the brake drum and fan construction of FIG. 2.

In the embodiment illustrated in FIG. 1, the reference numeral 5 designates a central shaft mounted for free rotation uponfriction-reducing bearings 6 and 6a in stationary supporting members 7 and 7a. A means for driving shaft 5 in either direction is illustrated as sprocket 8 connectible in driving relationship to shaft 5 through an air clutch 9. A spool, designated generally as It), includes cylindrical member 11 supported upon flanges 12 and 12a of hubs 13 and 13a. Hubs 13 and 13a are shrunk on shaft 5, keyed or otherwise rigidly connected thereto so that hubs 13 and members carried thereby rotate with the shaft.

A pair of outturned flanges 14 and 14a are carried by cylindrical spool member 11 near opposite ends thereof. These flanges are rigidly attached to cylindrical member 11 in any desired manner illustrated as by welds 15 and 15a and define a line-winding space 50 between them. A pair of brake drums 16 and 16a are carried by flanges 14 and 14a, respectively, at the periphery of the flanges.

Brake drums 16 and 16a have outer braking surfaces 17 and extend outward from the line-winding space parallel with the axis of shaft 5 and so are substantially cylindrical continuations of the periphery of flanges 14 and 14a. A pair of brake bands 18 are singly disposed to enclose brake surfaces 17 of the brake drums and are equipped in conventional manner with linings 19. The bands are of the external, contracting type and cooperate with the braking surfaces of the brake drums to apply friction to control rotation of spool 10.

A pair of stationary, cylindrical guard members 23 and 24 having closed end walls are disposed near the outer ends of spool and are so positioned that they define narrow, annular openings 25 between outer ends of brake drums 16 and 16a and the end walls of the guard members which are perpendicular to the axis of the spool. The guard members also have cylindrical, side wall portions 26 which overlie the brake drums and brake band and extend from the end walls 23 and 24 toward the line-winding space for a distance sufl-lcient to overlie the brakes and flanges 14 and 14a but do not project into the line-winding space. Space 27 between the periphery of flanges 14 and 14a is thus left open. Cylindrical wall sections 26 define spaces between the brake drums and wall section of substantially larger cross-sectional area than annular openings 25 between the ends of the brake drums and the end walls of the guard members.

This arrangement provides for a space between flanges 14 and 14a and corresponding end walls 23 and 24 of the guard members in which a pair of fans designated generally as 28 are arranged. These fans are of centrif-ugal type and include a plurality of straight, flat,

radial vanes 29 and 29a arranged to be driven by rotation of spool 10.

A series of openings 20 are provided in each of the flanges 14 and 14a and serve as inlets for air into a central part of centrifugal fans 28. These openings weaken flanges 14 and 14a somewhat, and we have found that it is preferable to brace the flanges by a series of flat plates 22 radially arranged in an inner central part of the spaces between flanges 14 and 14a and corresponding end walls 23 and 24 of the guard members.

The preferred type of fan illustrated comprises vanes 29 and 29a which are supported upon a pair of annular plates 30 and 31. These plates may be of very light construction, and it is preferred that plate 31 be attached to an inner surface of a brake drum as illustrated so that vanes 29 and 29a are held in cooperating relationship with a series of fins 32 on the inner surfaces of brake drums 16 and 16a. In order to make the fan light in weight, it is preferred that annular member 30 be of thin material, such as sheet steel, and that the edges of the vanes lying upon this member be welded or otherwise firmly attached thereto. In order to brace a light member of this type, it is preferred that a number of vanes 29a extend for a considerable distance further toward the center of the fan than vanes 29. The number of these that is required for bracing will depend upon the size of the fan. For example, alternate vanes may have the enlarged configuration shown at 29a, or as every fourth or sixth vane, the number depending upon the weight and thickness of member 311 and the size of the fan.

Vanes 29 and 29a cooperate with fins 32 to pass the entire effluent thrown outward by the fan across substantially the entire inner surface of brake drums 16 and 16a and through narrow, annular opening 25 between the end of the brake drum and the end wall of the corresponding guard member. The end wall of the guard member then deflects the stream of air radially outward and over the surfaces of the brake band when the brake band is in contact with the brake drum. When the brakes are released, there is also flow of air between brake lining 19 and braking surface 17 of drum 16 so that maximum cooling is obtained. This construction also provides for some cooling by expansion of air since cylindrical side wall 26 of the guard members provides spaces 33 between the brake bands and the walls which are much larger in cross-sectional area than small annular space 25 at the ends of the brake drum. Opening 27 also is much larger in cross section than narrow, annular opening 25 so that there is expansion of air, and the air is cooled by expansion while it is in heat-exchange contact with the brakes.

The modification shown in FIGS. 2 and 3 provides for a fan of larger capacity in a smaller space than that required in the embodiment shown in FIG. 1. In this embodiment, the brake drums are formed as shown at 34 and vanes 2% are made integral with the fins by providing a band of silver solder 35 or other heat transmitting connection between the inner surfaces of brake shoes 34 and vane 29b. In this modification, the vanes themselves conduct heat from brake drum 34 and so greatly increase the heat-transfer surface over which all incoming air flows.

Annular member 30 in this case is modified by decreasing its diameter as shown at 30a, and a larger path for passage of air to a corresponding annular opening 25 is provided. The arrangement of fins in series about the circumference of the fan is illustrated in FIG. 3 in which the vanes 29b are shown to be spaced at regular intervals around the circumference of a circle.

From the above description, it will be seen that the guard members cooperate with the brake drums to direct air flow in a path across the drums and brake bands to provide most effective heat exchange between the brake drums and bands with the stream of air. Fins on the inner sides of the brake drums both increase heat exchange area and perform the function of moving the air. Thus, even when constructed separately from the vanes, the fins serve as additions to the vanes in performing this function. The outlet for air flowing into the linewinding space provides a wide circumferentially continuous opening for inspection of brake conditions available to the operator at all times and protected by the discharge of an air current always flowing in the same direction from entrance of debris into the brakes.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A hoist comprising in combination a rotatable spool, including a pair of spaced outturned flanges defining a line-winding space between them; a pair of brake dr-ums each disposed upon a corresponding one of said flanges having external braking surfaces substantially aligned with the periphery of the flange, extending from a corresponding flange outward from said line-winding space parallel to a longitudinal axis of the spool; a pair of brake bands having inner braking surfaces cooperative with said external braking surfaces of the brake drums and means for passing currents of air across inside surfaces of said brake drums in directions away from said line-winding space and in reverse directions across said brake drums into said line-winding space including a pair of opposed stationary guard members having imperforate outer end walls perpendicular to a longitudinal axis of the spool each disposed near an outer end of a brake drum and defining an annular opening of relatively small cross-sectional area between the outer ends of the brake drum and end wall, and having a substantia'lly cylindrical side Wall extending from the end wall to the line-winding space defining a space radially outward from said brake bands of substantially larger cross-see tional area than said annular openings; a pair of centrifugal fans having straight, flat, radial vane-s, each carried by said spool between one of said flanges and a corresponding guard member; a series of fins extending radially inward from inner surfaces of said brake drums cooperating with said straight flat radial vanes and guard members to pass eflluents of air from said centrifugal fans across inside surfaces of said brake drums to impinge upon the imperforate outer wall of said guard member, through said annular openings and across said brake bands into the line-winding space.

2. A hoist comprising in combination a rotatable spool including a pair of outturned flanges defining a line-winding space between them; a brake drum carried by the flange having an external braking surface substantially aligned with the periphery of the flange extending out ward from the line-winding space parallel to a longitudinal axis of the spool; a brake band having an inner braking surface cooperative with said external braking surface of the brake drum; a stationary guard member disposed encircle the brake drum and brake band having an imperforate outer end wall substantially perpendicular to a longitudinal axis of the spool providing an annular space between the end wall and an outer end of the brake drum, said brake drum having a substantially cylindrical side wall extending from the end wall to the line-winding space defining a space radially outward from the brake band; and means for passing a current of air across the inside surface of the brake drum in direction away from the line-winding space to impinge upon said wall and in reverse direction across said brake band into said line-winding space including a centrifugal fan having straight flat radial vanes carried by said spool between the flange and guard member and a series of fins extending radially inward from an inner surface of the brake drum cooperating with said straight flat radial vanes and guard member to control direction of flow of an efiiueut of air from said centrifugal fan.

3. The hoist of claim 1 wherein a series of openings through said flanges provides air inlets to said fans.

4. The hoist of claim 1 wherein the fins on the inner surface of the brake drums are integral with the flat, radial vanes.

References Cited by the Examiner UNITED STATES PATENTS 1,536,667 5/25 Goeser l88264 1,874,574 8/32 Morgan l88264 1,966,169 7/34 Forbes l88264 2,042,750 6/36 VanHalteren l88264 2,129,115 9/38 Best l88264 2,317,171 4/43 Berby 254187 2,823,325 2/58 Stephan l88264 SAMUEL F. COLEMAN, Primary Examiner. 

1. A HOIST COMPRISING IN COMBINATION A ROTATABLE SPOOL, INCLUDING A PAIR OF SPACED OUTTURNED FLANGES DEFINING A LINE-WINDING SPACE BETWEEN THEM; A PAIR OF BRAKE DRUMS EACH DISPOSED UPON A CORRESPONDING ONE OF SAID FLANGES HAVING EXTERNAL BRAKING SURFACES SUBSTANTIALLY ALIGNED WITH THE PERIPHERY OF THE FLANGE, EXTENDING FROM A CORRESPONDING FLANGE OUTWARD FROM SAID LINE-WINDING SPACE PARALLEL TO A LONGITUDINAL AXIS OF THE SPOOL; A PAIR OF BRAKE BANDS HAVING INNER BRAKING SURFACES COOPERATIVE WITH SAID EXTERNAL BRAKING SURFACES OF THE BRAKE DRUMS AND MEANS FOR PASSING CURRENTS OF AIR ACROSS INSIDE SURFACES OF SAID BRAKE DRUMS IN DIRECTIONS AWAY FROM SAID LINE-WINDING SPACE AND IN REVERSE DIRECTIONS ACROSS SAID BRAKE DRUMS INTO SAID LINE-WINDING SPACE INCLUDING A PAIR OF OPPOSED STATIONARY GUARD MEMBERS HAVING IMPERFORATE OUTER ENDS WALLS PERPENDICULAR TO A LONGITUDINAL AXIS OF THE SPOOL EACH DISPOSED NEAR AN OUTER END OF A BRAKE DRUM AND DEFINING AN ANNULAR OPENING OF RELATIVELY SMALL CROSS-SECTIONAL AREA BETWEEN THE OUTER END OF THE BRAKE DRUM AND END WALL, AND HAVING A SUBSTANTIALLY CYLINDRICAL SIDE WALL EXTENDING FROM THE END WALL TO THE LINE-WINDING SPACE DEFINING A SPACE RADIALLY OUTWARD FROM SAID BRAKE BANDS OF SUBSTANTIALLY LARGER CROSS-SECTIONAL AREAA THAN SAID ANNULAR OPENINGS; A PAIR OF CENTRIFUGAL FANS HAVING STRAIGHT, FLAT, RADIAL VANES, EACH CARRIED BY SAID SPOOL BETWEEN ONE OF SAID FLANGES AND A CORRESPONDING GUARD MEMBER; A SERIES OF FINS EXTENDING RADIALLY INWARD FROM INNER SURFACES OF SAID BRAKE DRUMS COOPERATING WITH SAID STRAIGHT FLAT RADIAL VANES AND GUARD MEMBERS TO PASS EFFLUENTS OF AIR FROM SAID CENTRIFUGAL FANS ACROSS INSIDE SURFACES OF SAID BRAKE DRUMS TO IMPINGE UPON THE IMPERFORATE OUTER WALL OF SAID GUARD MEMBER, THROUGH SAID ANNULAR OPENINGS AND ACROSS SAID BRAKE BANDS INTO THE LINE-WINDING SPACE. 